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Non-singular covers over ordered monoid rings

Ladislav Bican (2006)

Mathematica Bohemica

Let G be a multiplicative monoid. If R G is a non-singular ring such that the class of all non-singular R G -modules is a cover class, then the class of all non-singular R -modules is a cover class. These two conditions are equivalent whenever G is a well-ordered cancellative monoid such that for all elements g , h G with g < h there is l G such that l g = h . For a totally ordered cancellative monoid the equalities Z ( R G ) = Z ( R ) G and σ ( R G ) = σ ( R ) G hold, σ being Goldie’s torsion theory.

On a special class of left-continuous uninorms

Gang Li (2018)

Kybernetika

This paper is devoted to the study of a class of left-continuous uninorms locally internal in the region A ( e ) and the residual implications derived from them. It is shown that such uninorm can be represented as an ordinal sum of semigroups in the sense of Clifford. Moreover, the explicit expressions for the residual implication derived from this special class of uninorms are given. A set of axioms is presented that characterizes those binary functions I : [ 0 , 1 ] 2 [ 0 , 1 ] for which a uninorm U of this special class exists...

On almost equitable uninorms

Gang Li, Hua-Wen Liu, János Fodor (2015)

Kybernetika

Uninorms, as binary operations on the unit interval, have been widely applied in information aggregation. The class of almost equitable uninorms appears when the contradictory information is aggregated. It is proved that among various uninorms of which either underlying t-norm or t-conorm is continuous, only the representable uninorms belong to the class of almost equitable uninorms. As a byproduct, a characterization for the class of representable uninorms is obtained.

On congruences and ideals of partially ordered quasigroups

Milan Demko (2008)

Czechoslovak Mathematical Journal

Some results concerning congruence relations on partially ordered quasigroups (especially, Riesz quasigroups) and ideals of partially ordered loops are presented. These results generalize the assertions which were proved by Fuchs in [5] for partially ordered groups and Riesz groups.

On homological classification of pomonoids by GP-po-flatness ofS-posets

Xingliang Liang, Xinyang Feng, Yanfeng Luo (2016)

Open Mathematics

In this paper, we introduce GP-po-flatness property of S-posets over a pomonoid S, which lies strictly between principal weak po-flatness and po-torsion freeness. Furthermore, we investigate the homological classification problems of pomonoids by using this new property. Finally, we consider direct products of GP-po-flat S-posets. As an application, characterizations of pomonoids over which direct products of nonempty families of principally weakly po-flat S-posets are principally weakly po-flat...

On homological classification of pomonoids by regular weak injectivity properties of S-posets

Xia Zhang, Valdis Laan (2007)

Open Mathematics

If S is a partially ordered monoid then a right S-poset is a poset A on which S acts from the right in such a way that the action is compatible both with the order of S and A. By regular weak injectivity properties we mean injectivity properties with respect to all regular monomorphisms (not all monomorphisms) from different types of right ideals of S to S. We give an alternative description of such properties which uses systems of equations. Using these properties we prove several so-called homological...

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